This invention relates to the production of carbonated candy which is a hard candy containing carbon dioxide gas as disclosed in U.S. Pat. No. 3,012,893 which is herein incorporated by reference. Ideally, such a carbonated candy when placed in the mouth produces an entertaining popping sensation. However, to obtain a successful product, it is necessary to control the processing in a number of critical areas. The preparation of the candy melt should be prepared with a minimum of heat treatment in order to limit hydrolysis and decomposition of its sugar constituents. Both hydrolysis and decomposition can soften the candy glass which prevents a good "pop" in the product. The influence of temperature on cooked candy while gas is being added is an important variable. It is believed that the viscosity of the cooked mass has an effect on the gas incorporation. Thus, if the melt is allowed to cool too much, the candy will have little "pop" since the gas will not mix with the melt at reduced temperatures.
Candy glasses are sensitive to moisture. Moisture make candy glasses less brittle or more pliable. As the candy becomes less brittle, due to either excess moisture or heat, crystallization of the sugar can occur. This crystalline state allows the gas to more readily escape. The moisture content of the final product is preferably just below about 2.5%. If the moisture content is higher, the candy becomes less brittle and more tacky.
The mechanism for incorporation of the gas in glass is one of dividing gas bubbles into minute dimensions. The thickness of the walls surrounding the gas bubbles must be sufficient when solidified to hold the pressure exerted by the gas. At any given pressure, the smaller the gas bubble the smaller can be the thickness of the wall of candy glass in order to contain the pressure. While other gases may be used, such as nitrogen or nitrous oxide, it is most desirable to use carbon dioxide since it imparts an acid sourness and tingle which is not present in other gases.
Ideally, the candy glass contains 4 to 6 cc. of CO.sub.2 per gram. When CO.sub.2 is introduced under pressure to a vessel containing a candy melt, the resultant product contains only up to about 2 cc. per gram of CO.sub.2. It has been found that it is necessary to agitate the melt at relatively high speed, i.e., over 1200 R.P.M., in order to incorporate greater amounts of gas in the product. Additionally, it has been found that a relatively large headspace must be maintained above the level of the melt within the vessel. Means must be provided to disperse the gas in the bottom of the vessel. Thus, agitator must operate a speed sufficiently high enough to create a vortex within the vessel so that the gas may be drawn into the agitator blades which are generally located near the bottom of the vessel. The combination of high shaft speed and headspace permits a violent churning and mixing action to take place within the vessel, thus allowing more gas to be admitted to the melt than if the melt were gently mixed or quiescent.
Therefore, it would be highly desirable if a simple method were devised to easily incorporate greater volumes of CO.sub.2 within a candy glass without excessive agitation.